Electric heater



LJn. 31, 1928.

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ADOLF STEFFENQ'OF PITTSBURGH, PENNSYLVANIA,

' 00., INC., A CORPORATION OF PENNSYLVANIA.

AssTGNoa To Annius ELECTRIC HEATER.

Application led August 11, 1925. Serial No. 49,540.

My invention relates to heating units and particularly to electric wall heaters.

One object of my invention is to provide a relatively simple, compact, and inexpensive electricheater.

Another object of my invention is to provide an electric heater of light weight that may be easily and quickly mounted in a wall, and that will permit of removing and inserting the electric heating unit from the front thereof. I

In practicing my invention, I provide a metal frame, having an opening therein, and a dished metal member having a plurality of bars of refractory electric-insulating material located therein which support a resistor member at their front surfaces. plurality of metal casings are located back of the metal frame to enclose lthe heating unit and a control switch, at the back thereof. Means integral with the frame are provided to permit air to circulate through said casings to cool the saine.

in the drawings,

Figure 1 is a view, in front elevation, of an electric heater embodying my invention,

F ig. 2 is a view, in vertical section therethrough, taken on the line Iiwlbf Fig. 1,

Fig. 3 is a view, in rear elevationtof an electric heating unit embodying my invention,

Fig. i is a view, end elevation thereof, and,

Fig. 5 is a fragmentary line V-V of Fig. 1. 1

A heater 11 comprises a metal frame 12 that is preferably made of relatively thin, substantially dat metal, in the form of a casting, having a lower. opening 13 and an upper opening 14 therein, each opening being of substantially rectangular contour. An inte ral peripheral flange portion 15 is provided on the frame 12, and extends backwardly therefrom at substantially right angles thereto, as shown more particularly in Fig. 2 of the drawings. A forwardly-projecting hood portion 16 is provided immediately above the upper openingA 14 and serves a plurality of purposes to be hereinafter set forth.

An elect-ric heating unit 17, normally operatively supported by the frame, comprises a dished metal member 18, of substantially rectangular contour, that has a plurality of openings 19 and 21 in its bottom portion.

view, taken on the The metal walls of the member 18 are made 'relatively thin in order that it maybe light in weight and that it may have a relatively small heat-storage capacity. It is provided with integral notched supporting lugs 22 and 23, located at the two sides thereof, and with an integral securing lug 24 at thc bottom portion, the lug having a screw-threaded opening 25 therein.

A plurality of bars 26, of refractory electric-insulating material, are located in sideby-side relation in the member 17, their ends operatively engaging integral bottom portions of thev member 17, and covering the two openings 19 and 21. Each of the bars 26 comprises a body portion 27 and a relatively narrow top portion 28, extending in zigzag shape along the body portion. A plurality of laterally-extending openings 29 are located partially in the body portion and partially in the top portion. A helically `wound ed by the bars 26-and extends through the openings 29. This provides a heating element that extends substantially uniformly over the surface occupied by the bars 26.

Each of the bars 26 is further provided with two spaced openings 82 extending laterally through the body portion adjacent to the two ends thereof, and a metal wire or rod 33 extends through each of these openings, whereby the bars are maintained in their proper operative positions relatively to each other. The rods 33 are made long enough to extend through the end flanges of the member 17 (asV shown more particularly in Fig. 3) and are each provided with a return bent end portion 34 at one end thereof, and a screw-threaded end portion 35 at the other end thereof, having a nut 36 located thereon. Insulating bushings 37 are mounted on the rods 33 adjacent to the end portions thereof, to insulate the rods from the flange portions ot' the member 17.

he resistor member 31 that is supported by the bars 26 covering the opening 19 is preferably made of a single length of wire, the two ends of which are connected to the return-bent end portions 34 of the two bars 33 supporting the bars 26. The ends of the wire may be secured to the return-bent portions 34 by machine screws 38 having nuts 39 mounted thereon. The same construction is employed in the other half of the heating unit, that is, in those bars covering the open- BROS. MFG.

resistor member 31 is support-l ing 21, and the return bent portions of the /two rods 33 located closely adjacent to each other are so located that one is super osed on the other as is shown in Figs. 3 an 4 of the drawings. A single machine screwA 38 extending therethrough serves not only to hold the two halves of the heating unit in proper operative positions relatively to each other, but serves also to eect the electrical connection of the two ends of the resistors to the rods, and also serves to electricall connect the two parts of the resistor to eac thor.

An inner casing 41 is provided, and is made of relatively thin sheet metal. It is fitted against the rear surface of the member 12 and its dimensions, both laterally and longitudinally are such that it extends around the two openings'13 and 14. A plurality of lugs 42 are cast integral with the rear surface of the frame 12 and the casing 41 is held in its proper operative position by machine screws 43 extending through the sides of the casing 41 and into the lugs 42. An outer casing 44, also made of thin sheet metal, is somewhat larger in all of its dimensions than the inner casing 41 in order to provide an air space between the two casings at the back of the frame 12. A plurality of integral lugs 45 are provided and the outer casing 44 is secured in its proper operative position at the back of the frame 12 by machine screws 45 extending through the side walls of the casing and into the lugs 45.

A member 47, of substantially U-shape, has its intermediate portion secured against the inner surface of the inner casing 41 substantially centrally of the opening 13. A switch 48, here shown as a toggle switch, is supported by the member 47 in such manner that the operating member thereof projects through a suitable opening in an ornamental cover plate 49 that is provided to close the opening 13. The front surface of the plate 49 may be ornamented in an suitable or desired manner and is provi ed with a plu rality of Vopenings 51 therein and with a suitable space to receive a name plate 52. The member 49 is held by two machine screws 53 at the edges thereof. A suitable bushing 54 extends through the rear walls of the inner and of the outer casings and is provided with a screw-threaded nut 55 thereon, to permit of introducing the supply circuit conductors into the interior of the inner casing where connection may be made to the control switch 48.

namens part of the heater lying back of the edge of the flange portion '15 is adapted to fit. The recesses 57 permit air toenter and then to ow through the openings 56 into the space between the inner and theouter casings toward the upper part of the heater and then downwardly back of the hood 16. This cools the reagr part of the heater unit and prevents any excessive rise of temperature of the outer casing which may be located quite close to portions of the wood structure of the wall. Air mayv also enter through the openings 51 in the plate '49 and flow past the switch 48 and upwardly back of the heater unit and outwardly under the hood 16. In this vvay convection currents.

of air are established which make use of the heat that might otherwise be lost from the back part of the heat-er, these currents of air flowing out into the room to heat the same.

`Air will also dow along the front of the heater, particularly so as the resistors are to be operated at a radiant heat, and the amount of energy translated into heat is relatively large in a heater unit of this kind. The heated air strikesthe upper beveled face of the dished member 18, and there is a marked tendency to deposit dust on this beveled face. As I preferably cover the entire front surface of the frame 12 and of the closure member 49 with white enamel in order to obtain a decorative effect, it is highly desirable that the accumulation of dust on the enameled surface be prevented.

I have found that the hood 16 tends to prevent the deposit of dust on the front surface of the frame above the heating unit, for as noted above, any dust in the air heated at the front of the heating unit is deposited on the upper ,beveled face of the member 18.

A pair of hooked members 58, made of wire, are provided adjacent to the sides of the upper opening 14 and have one end thereof cast into the frame, this construction being shown in the fragmentary' view of Fig. 5. The assembled heating unit as shown in Figs. 3 and 4 of the drawings may be easily and quickly placed in its proper operative position in the frame 12 by moving it into its place therein, tilted and turned from its final operative position in order to permit it to enter the opening 14.

It is then so moved as to make the plane,

thereof substantially parallel with the plane of the member 12 and the notches in the lugs 22 and 23 are then caused to rest upon the supporting members 58. lf the cover plate 49 has been removed it is possible to cause a machine screw 59 to project through a lug 61 on the rear surface of the frame immediately7 below the opening 14 and to cause it to enter the screw-threaded opening 25 in the lug 24. In this way the heating `unitcomprising the dished member 18 is i above described methodof supporting the heating unit provides a minimum number of supporting points together with a sin le point at which a steadying connection etween the two parts is provided. This ensures that substantially all of the heat generated in the heating element will be available for radiation in a forwardly direction, either directly from the resistor, or reflected from the beveled front surfaces of the dished member 18.

The frame 12 may be provided with a plurality of openings 63 at the respective corners through which suitable securing screws may extend into the wall against, and in which, it is to be located.

Various modifications may be made in the device embodying my invention without departing from the spirit and scope thereof, and all such modifications are intended to be covered by the appended claims.

,I claim as my invention 1. In an electric heater, in combination, a main frame ,having an opening therein, supporting lugs secured to said frame at the two sides ofthe opening and extending rearwardly therefrom, a heating unit insertible from the front into said opening and having a hook member at each side thereof for engaging the supporting lugs.

2. In an electric heater, in combination, a main frame having an opening therein, a rearwardly extending supporting 1u secured f to said frame at each side of t e opening, a heating unit insertible into and removable from said frame through said opening and having a hook member at each side thereof for engaging the supporting lugs,

and means at the bottom of said opening for holding the heating unit tightly on said supporting lugs.

3. In an electric heater, in combination, a main frame having an opening therein, a rearwardly-extending supporting lug secured to said frame at each side of the opening, a heating unit embodyinga dished frame and a hook member at each side of the frame for enaging a-supporting lug, the cooperating ook and lug being so shaped as to hold the dished frame away from the main frame to reduce heat flow therebetween.

4. In un electric heater, a light weightradiant heating unit .comprising a dished vmetal frame having an opening in the bottom thereof, a plurality of refractory bars located in side-by-side 1ocation in said opening openings therethrough, a. resistor member. extending through said openings and dis'- tributed uniformly over the front surface of said set of bars, and a pair of spaced rod members extending through the refractory bars and through said metal frame for holding them in said frame opening.

5. In an electric air heater, in combination, a, main frame having` an opening therein, a forwardly removable heating unit embodying a dished frame having an open bottom, refracto bars in the open bottom and a heating e ement supported by said bars, and two cooperating hook members on each of said frames for supporting the dished frame in said main frame opening, and out of engagement with said main frame.

6. In an electric air heater, in combination, a main frame having an opening therein, a heating unit embodying a dished metal frame forwardly removable from said main frame opening, and cooperating means on the said frames for su porting the heating unit from said main ii'ame at two space points only.l

In testimony whereof, I have hereunto subscribed my name this 4th day of August, 1925.

ADOLF STEFFEN.

in combination,

and having alinedl 

